Superheater



Patented Mar. 26, 1929.

,UMTED [STATES 1mm SCHNEIDER, or KELHEIM-DONAU, GERMANY, nssrenon 'Tomanna-BAYER- ISCHE CELLULOSEWERKE LAKTIENGESELIISGHAFT, OF KELI-IEIM ONTHE DANUBIE,

GERMANY.

SUPERHEA'IER.

Application filed April 22, 1926, Serial .No. 1'03, 9 39, and in GermanyAugust 19, 1925.

This invention relates tomovable superheaters of the type which areheated by radiation, in contradistinction to superheaters in which thesuper-heater tubes are heated solely by contact with the of combustion.

It has already been proposed to superhea'tsteam by ineans of movablesuperheaters the latter being movable into or outof the stream ofheating gases, to a greater or lesser extent. Superheaters of this typereceivetheir heat only fromthe hot gases, and do nottherefore use up theradiant heat of theburning fuel. The heating surfaces must on thataccount be of unnecessarily large dimensions, which entails the furtherdisadvantage that the uniform heating of the superheater tubes by thehot gases is difiicult to ensure, so that individual tubes may easily beburnt through. Further when the temperature of the hot gases varies thedifficulty of regulating the superheater to a constant temperature isgreater the greater theheatingsurface of the superheater and the lowerthe temperature of. the heat transmitting medium.

In order to obviate these disadvantages, movable superheaters have beenproposed, which can be moved to a greater or lesser extent behindheating tubes, in order to be able to expose them in this way to theradi ant heat of the furnace to a greater or lesser extent. Superheatersof the above mentioned type possess the disadvantage, that they are toopowerfully cooled by the water-conveying heating tubes serving asscreens, and that the hot gases cannot flow round the superheater tubesadequately, being prevented from doing so by the heating tubes. Theradiant heat of the gas stream itself, as well as the contactheat, canonly be imperfectly transmitted when the above mentioned type ofsuperheater tube is employed. In practice, the above mentioned type ofsuperheater has the disadvantage that the position can only be changedby a longitudinal movement a of the super-heater, parallel, for example,to the water tubes so that the distance ofthe superheater from, or itsposition in, the stream of hot gases, and its position with respect tothe fire cannot be altered. This drawback in its turn causesdisadvantages from the point of view of both heat and tem peratureregulation. Further the movement of the superheater by displacement isalso point of ther drawback that the superheater tubes are inthe form ofU-shaped 100 as so that thereis consulerable risk of thetu becomingammed in the packln g means.

The object of the present invention is to obviate all the abovementioneddisadvantages, and produce a superheatcr having new advantages. p

The invention is illustrated, by way of example, in the accompanyingdrawings, in which:

Fig. l is a cross section of a steam boiler" provided with a radiationsuperheater which is also capable of removing the heat from the hotgases.

Fig. .2 is a side view of a superheater element and Fig. 3 shows severalsuperheater elements to ether with their rotary device.

eferring to the drawings, a is a preheater for air or feed-water, whichis heated by the flue-gases from the furnace 7a. of the medium or lowpressure boiler b. A Field tube boiler 0 is interposed in front of theboiler Z), and serves as a high pressure boiler, receiving its feedwater from the boiler Z) and being heated by the furnace it into whichthe Field tubes Z depend. At the rear end of the furnace h is a wall onwhich is capable of obstructing the passage of radiant heat from theburning fuel, which is placed on the grate n, and mounted above the wallon inside the boiler is a superheater cZ comprising a plurality of tubesbent into the form of annular loops. The superheater (Z is pivotedeccentrically with respect to the centres of the loops so as to becapable of being turned from the position shown in full lines in Figure1 where it rests on the wall at into the position shown in broken linesbehind the wall 71 Behind the wall at is a space positions, according tothe angle 0:.

o' forming a fiuedust bunker, said space having an opening 70 at thebottom which communicates with the ashpit p. In the position'indicatedby broken lines the superheater is Withdrawn from the radiant heat ofthe fire, as well as from thestream of hot gases. The greatestsuperheater temperature is attained when the superheater is in the position indicated in fulllines. The temperature can be regulated in betweenthe two It is to be'understood that the invention is not limited to thekinds of; boilers, nor to the particular boiler arrangement hereinbeforedescribed.

The tube coils e, are so arranged in Figs. 2 and-3 that each coil .6lies in a plane, the superheater tubes being wound in and out sinuously.

The individual elements may however be wound .in any other manner, andif preferred they maybe bent out of; the plane, whereby the'transfer ofheat is improved.

' are rotatably mounted in the form of stuffing boxes. 41 is a devicefor turning the superheater. The two headers f 9' may be united into onesingle header.

1: What. Iolaim is In Fig. 3 these headers 1. In combination, a steamboiler having a furnace constituting a source of radiant heat within theboiler, said furnace having a wall capable of obstructing the passage ofradiant heat, a flue dust bunker within the furnace behind said wall,and a superheater comprising a plurality of tubes bent into the form ofannular loops and pivoted in the boiler in proximity to said furnacewall and eccentrically with respect to the centres of the loops so as tobe capable of being turned into a position projecting beyond said wallfor enabling it to be heated by radiant heat from the furnace and ofbeing turned out of said position behind said wall into the flue dustbunker, as set forth.

2. In combination, a steam boiler having a furnace constituting a sourceof radiant heat within the boiler, said furnace having a wall capable ofobstructing the passage of radiant heat, a flue dust bunker within thefurnace behind said wall, and a superheater comprising a plurality ofsinuously wound tubes bent into the form of annular loops and pivoted inthe boiler in proximity to said furnace wall and eccentrically withrespect to the centres of the loops so as to be capable of being turnedinto a position projecting beyond said wall for enabling it to be heatedby radiant heat from the furnace and of being turned out of saidposition behind said wall into the flue dust bunker, as set .forth.

In testimony whereof I have signed my name to this specification.

ADOLF SCHNEIDER.

